Intrinsic ferromagnetism in insulating cobalt doped anatase TiO2 -: art. no. 157204

Using complementary experiments we show that the room temperature ferromagnetism observed in anatase CoTiO2 films is not carrier mediated, but coexists with the dielectric state. TEM and x-ray absorption spectroscopy reveal a solid solution of Co in anatase, where Co is not metallic but in the +2 state substituting for Ti. Measurements at 300 K yield a M-S of 1.1 mu(B)/Co atom, while all films are highly insulating. The evidence of intrinsic ferromagnetism in the dielectric ground state of CoTiO2 leads to new considerations for the origin of ferromagnetism in transition metal doped oxides.